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Hydrogen peroxide (H 2 O 2 ) is a reactive oxygen species (ROS) that can be used as a marker for the occurrence of oxidative stress in the organism. Lysosomes serve as intracellular digestive sites, and when the concentration of H 2 O 2 in them is abnormal, lysosomal function is often impaired, leading to the development of diseases. Hydrogen sulfide (H 2 S) acts as a gaseous signaling molecule that scavenges H 2 O 2 from cells and tissues, thereby maintaining the redox environment of the body. However, most of the reported hydrogen peroxide fluorescent probes so far can only detect H 2 O 2 , but cannot maintain the intracellular redox environment. In this paper, an H 2 O 2 fluorescent probe LN-HOD with lysosomal targeting properties was designed and synthesized by combining the H 2 O 2 recognition site with a naphthylamine fluorophore via a thiocarbamate moiety. The probe has the advantages of large Stokes shift (110 nm), high sensitivity and good H 2 S release capability. The probe LN-HOD can be used to detect H 2 O 2 in cells, zebrafish and plant roots. In addition, LN-HOD detects changes in the concentration of H 2 O 2 in plant roots when Arabidopsis is stressed by cadmium ion (Cd 2+ ). And through its ability to release H 2 S, it can help to remove excess H 2 O 2 and maintain the redox environment in cells, zebrafish and plant roots. The present work provides new ideas for the detection and assisted removal of H 2 O 2 , which contributes to the in-depth study of the cellular microenvironment in organisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The continuous supply of hydrogen sulfide (H 2 S) gas at high concentrations to tumors is considered a promising and safe strategy for tumor therapy. However, the absence of a durable and cost-effective H 2 S-producing donor hampers its extensive application. Sulfate-reducing bacteria (SRB) can serve as an excellent H 2 S factory due to their ability to metabolize sulfate into H 2 S. Herein, a novel injectable chondroitin sulfate (ChS) hydrogel loaded with SRB (SRB@ChS Gel) is proposed to sustainably produce H 2 S in tumor tissues to overcome the limitations of current H 2 S gas therapy. In vitro, the ChS Gel not only supports the growth of encapsulated SRB, but also supplies a sulfate source to the SRB to produce high concentrations of H 2 S for at least 7 days, resulting in mitochondrial damage and immunogenic cell death. Once injected into tumor tissue, the SRB@ChS Gel can constantly produce H 2 S for >5 days, significantly inhibiting tumor growth. Furthermore, such treatment activates systemic anti-tumor immune responses, suppresses the growth of distant and recurrent tumors, as well as lung metastases, meanwhile with negligible side effects. Therefore, the injectable SRB@ChS Gel, as a safe and long-term, self-sustained H 2 S-generating factory, provides a promising strategy for anti-tumor therapy., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

A cellulose based polymer probe (HC-HS) was prepared for the detection of H 2 S. HC-HS can be applied to fluorescence imaging of H 2 S in living cells and zebrafish, and HC-HS was made into test strips to detect H 2 S produced in the process of food corruption.

Delayed wound healing is one of the major diabetes complications that occur in 25% of diabetic patients. Specific wound management and combination treatment are required to repair the wound, which still remains a challenge with few effective therapies available currently. In this work, a new H 2 S donor PRO-F , which is characterized by the capability to promote wound healing in diabetes, was designed. PRO-F can be activated by light without consuming endogenous substances and the accompanying fluorescent signal makes the real-time tracking of released H 2 S possible. PRO-F is able to deliver H 2 S in an intracellular environment with moderate release efficiency (50%), which presents cytoprotective effects against excessive reactive oxygen species (ROS) induced damage. Furthermore, the potential of PRO-F to enhance chronic wound healing was validated by employing diabetic models. This work provides new insights into the therapeutic role of H 2 S donors in complex wound conditions, which should advance the pathophysiological research associated with H 2 S.

We present a new two-photon fluorescent probe (T-HS) for the detection of H 2 S. With the addition of hydrogen sulfide, the absorption and fluorescence spectra of the probe show regular changes. The probe exhibited favorable properties, such as large turn-on fluorescence signal, good selectivity and low cytotoxicity. Moreover, the probe T-HS was successfully used for the fluorescence imaging of H 2 S in live cells and zebrafish.

Hydrogen sulfide (H 2 S) is a vital endogenous signal molecule that exerts critical physiological functions such as biological regulation and cytoprotection. Despite significant progress in developing H 2 S donors, site-specific delivery and controllable release of H 2 S in biological systems remain a key challenge. Herein, we develop new Cys-triggered fluorescent H 2 S donor Pro-S that is composed of a dicyanoisophorone-based near-infrared (NIR) fluorescent dye and a thiocarbamate moiety. The H 2 S donor releases H 2 S under the attack of Cys, accompanied by the release of a fluorescent reporter, which enables the real-time capturing of H 2 S by fluorescence spectroscopy or microscopy. Pro-S exhibits strong NIR fluorescence enhancement (70-fold), excellent controllable H 2 S release (30 min), high H 2 S release efficiency (62%), and well live-cell compatibility, allowing for visualization of H 2 S release in cells and zebrafish. Moreover, Pro-S presents a good effect of anti-inflammation in RAW 264.7 cells. This work provides a new idea for the design of H 2 S donors, which may be beneficial to the comprehension of the potential mechanism of inflammation and optimization of treatment strategies.

Multiple types of metal ions and active small molecules (reactive nitrogen species, reactive oxygen species, reactive sulfur species, etc.) exist in living organisms. They have connections to each other and can interact and/or interfere with each other. To investigate the relationship of metal ions and active small molecules in living cells, it is necessary and critical to develop molecular tools that can track two kinds of associated certain metal ions and reactive molecules with multiple fluorescence signals. However, this is a challenging task that requires an ingenious molecular design to achieve this goal. Here, we present a fluorescent probe (D-CN) that can offer fluorescence imaging of H 2 S and copper (II) ions with different response signals. Recognition of H 2 S and Cu (II) by the new probe can result in green and red emissions, respectively, providing different signal responses to the two substances in living cells and zebrafish. In addition, we used this probe to visually prove that the cytotoxicity of copper ions in living cells increases in the presence of hydrogen sulfide and could lead to cell apoptosis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Fluorescence detection of H 2 S in living organisms is greatly advantageous because it is nondestructive and can be used for in situ analysis. We have constructed a novel rhodamine analogue dye (Rho630) by extending the conjugated system of rhodamine to create a novel cell-trappable H 2 S fluorescent probe Rho630-AM-H 2 S with red light emission. Its application for H 2 S fluorescence detection in living HeLa cells and zebrafish was investigated. As expected, Rho630-AM-H 2 S showed a huge fluorescence turn-on response of about 20-fold at 630 nm and good selectivity toward H 2 S in solution. An MTT assay demonstrated that the probe showed negligible cytotoxicity in the concentrations typically used in fluorescence imaging experiments. Cell imaging experiments revealed that compared with compound 4 without cell-trappable unit modification, Rho630-AM-H 2 S exhibited remarkably enhanced cell penetration ability, as an enormous fluorescence signal increase was observed at the red channel within 5 min after Rho630-AM-H 2 S was incubated with HeLa cells. Finally, the probe Rho630-AM-H 2 S was used to detect H 2 S in living HeLa cells and zebrafish with great fluorescence enhancement in the red channel. Graphical abstract.